COMP 2711 Ex 11

1

$$\begin{array}{rl}E(X)& =E(X_1+X_2+\cdots +X_n)\\ & =E(X_1)+E(X_2)+\dots E(X_n)\\ & =\underset{n}{\underbrace{\frac{7}{2}+\frac{7}{2}+\cdots +\frac{7}{2}}}\\ & =\frac{7n}{2}\end{array}$$

2

$$\begin{array}{rl}E(X)& =E(X_1+X_2+\cdots +X_{24})\\ & =E(X_1)+E(X_2)+\cdots +E(X_{24})\\ & =\underset{24}{\underbrace{\frac{1}{6}+\frac{1}{6}+\cdots +\frac{1}{6}}}\\ & =\frac{24}{6}\\ & =4\end{array}$$